Two-dimensional fluorescence spectroscopy - a new tool for the determination of plant cell viability

Two-dimensional fluorescence spectroscopy (2D-FS) has been used as a new me thod for determining the viability of tobacco cells (Nicotiana tabacum L.). Both horizontal beam geometry and a vertical setup achieved with bifurcate d fibres were tested. The latter arrangement enabled us to avoid the negati ve effect of cell sedimentation. Incubation of a tobacco BY-2 cell suspensi on with dimethylsulfoxide (DMSO) (0-10% v/v) resulted in cell samples diffe ring in their viability - from fully viable (0-2% DMSO) to totally non-viab le (8-10% DMSO). The validity of determining viability by means of measurin g cell esterase activity by 2D-FS using fluorescein diacetate as a fluoroge nic substrate was verified by comparison with microscopic evaluation of flu orescein fluorescence as well as with the routinely adopted trypan blue exc lusion test.